Method of image enhancement

ABSTRACT

An image  2  from a digital camera is modified by employing the output from an auto exposure setting stage  1  in an image processing step  3  to provide an enhanced processed image  4  as a function of said output.

[0001] Continuation Application Of U.S. Ser. No. 09/112,743 filed on Jul. 10, 1998

CROSS REFERENCES TO RELATED APPLICATIONS

[0002] The following patent applications are hereby incorporated by cross-reference. For the purposes of location and identification, US patent applications identified by their US patent application serial numbers (USSN) and US patents identified by their Patent Numbers are listed with Australian applications from which the US patents or patent applications claim the right of priority and the Applicant's Docket No. CROSS-REFERENCED U.S. PATENT/ AUSTRALIAN PATENT APPLICATION PROVISIONAL (CLAIMING RIGHT OF PATENT PRIORITY FROM AUSTRALIAN DOCKET APPLICATION NO. PROVISIONAL APPLICATION) NO. PO7991 09/113,060 ART01 PO8505 09/113,070 ART02 PO7988 09/113,073 ART03 PO9395  6,322,181 ART04 PO8017 09/112,747 ART06 PO8014 09/112,776 ART07 PO8025 09/112,750 ART08 PO8032 09/112,746 ART09 PO7999 09/112,743 ART10 PO7998 09/112,742 ART11 PO8031 09/112,741 ART12 PO8030  6,196,541 ART13 PO7997  6,195,150 ART15 PO7979 09/113,053 ART16 PO8015 09/112,738 ART17 PO7978 09/113,067 ART18 PO7982 09/113,063 ART19 PO7989 09/113,069 ART20 PO8019 09/112,744 ART21 PO7980  6,356,715 ART22 PO8018 09/112,777 ART24 PO7938 09/113,224 ART25 PO8016  6,366,693 ART26 PO8024 09/112,805 ART27 PO7940 09/113,072 ART28 PO7939 09/112,785 ART29 PO8501  6,137,500 ART30 PO8500 09/112,796 ART31 PO7987 09/113,071 ART32 PO8022 09/112,824 ART33 PO8497 09/113,090 ART34 PO8020 09/112,823 ART38 PO8023 09/113,222 ART39 PO8504 09/112,786 ART42 PO8000 09/113,051 ART43 PO7977 09/112,782 ART44 PO7934 09/113,056 ART45 PO7990 09/113,059 ART46 PO8499 09/113,091 ART47 PO8502 09/112,753 ART48 PO7981  6,317,192 ART50 PO7986 09/113,057 ART51 PO7983 09/113,054 ART52 PO8026 09/112,752 ART53 PO8027 09/112,759 ART54 PO8028 09/112,757 ART56 PO9394 09/112,758 ART57 PO9396 09/113,107 ART58 PO9397  6,271,931 ART59 PO9398  6,353,772 ART60 PO9399  6,106,147 ART61 PO9400 09/112,790 ART62 PO9401  6,304,291 ART63 PO9402 09/112,788 ART64 PO9403  6,305,770 ART65 PO9405  6,289,262 ART66 PP0959  6,315,200 ART68 PP1397  6,217,165 ART69 PP2370 09/112,781 DOT01 PP2371 09/113,052 DOT02 PO8003 09/112,834 Fluid01 PO8005 09/113,103 Fluid02 PO9404 09/113,101 Fluid03 PO8066  6,227,652 IJ01 PO8072  6,213,588 IJ02 PO8040  6,213,589 IJ03 PO8071  6,231,163 IJ04 PO8047  6,247,795 IJ05 PO8035 09/113,099 IJ06 PO8044  6,244,691 IJ07 PO8063  6,257,704 IJ08 PO8057 09/112,778 IJ09 PO8056  6,220,694 IJ10 PO8069  6,257,705 IJ11 PO8049  6,247,794 IJ12 PO8036  6,234,610 IJ13 PO8048  6,247,793 IJ14 PO8070  6,264,306 IJ15 PO8067  6,241,342 IJ16 PO8001  6,247,792 IJ17 PO8038  6,264,307 IJ18 PO8033  6,254,220 IJ19 PO8002  6,234,611 IJ20 PO8068 09/112,808 IJ21 PO8062  6,283,582 IJ22 PO8034  6,239,821 IJ23 PO8039 09/113,083 IJ24 PO8041  6,247,796 IJ25 PO8004 09/113,122 IJ26 PO8037 09/112,793 IJ27 PO8043 09/112,794 IJ28 PO8042 09/113,128 IJ29 PO8064 09/113,127 IJ30 PO9389  6,227,653 IJ31 PO9391  6,234,609 IJ32 PP0888  6,238,040 IJ33 PP0891  6,188,415 IJ34 PP0890  6,227,654 IJ35 PP0873  6,209,989 IJ36 PP0993  6,247,791 IJ37 PP0890 09/112,764 IJ38 PP1398  6,217,153 IJ39 PP2592 09/112,767 IJ40 PP2593  6,243,113 IJ41 PP3991  6,283,581 IJ42 PP3987  6,247,790 IJ43 PP3985  6,260,953 IJ44 PP3983  6,267,469 IJ45 PO7935  6,224,780 IJM01 PO7936  6,235,212 IJM02 PO7937  6,280,643 IJM03 PO8061  6,284,147 IJM04 PO8054  6,214,244 IJM05 PO8065  6,071,750 IJM06 PO8055  6,267,905 IJM07 PO8053  6,251,298 IJM08 PO8078  6,258,285 IJM09 PO7933  6,225,138 IJM10 PO7950  6,241,904 IJM11 PO7949 09/113,129 IJM12 PO8060 09/113,124 IJM13 PO8059  6,231,773 IJML4 PO8073  6,190,931 IJM1S PO8076  6,248,249 IJM16 PO8075 09/113,120 IJM17 PO8079  6,241,906 IJM18 PO8050 09/113,116 IJM19 PO8052  6,241,905 IJM20 PO7948 09/113,117 IJM21 PO7951  6,231,772 IJM22 PO8074  6,274,056 IJM23 PO7941 09/113,110 IJM24 PO8077  6,248,248 IJM25 PO8058 09/113,087 IJM26 PO8051 09/113,074 IJM27 PO8045  6,110,754 IJM28 PO7952 09/113,088 IJM29 PO8046 09/112,771 IJM30 PO9390  6,264,849 IJM31 PO9392  6,254,793 IJM32 PP0889  6,235,211 IJM35 PP0887 09/112,801 IJM36 PP0882  6,264,850 IJM37 PP0874  6,258,284 IJM38 PP1396 09/113,098 IJM39 PP3989  6,228,668 IJM40 PP2591  6,180,427 IJM41 PP3990  6,171,875 IJM42 PP3986  6,267,904 IJM43 PP3984  6,245,247 IJM44 PP3982 09/112,835 IJM45 PP0895  6,231,148 IR01 PP0870 09/113,106 IR02 PP0869 09/113,105 IR04 PP0887 09/113,104 IR05 PP0885  6,238,033 IR06 PP0884 09/112,766 IR10 PP0886  6,238,111 IR12 PP0871 09/113,086 IR13 PP0876 09/113,094 IR14 PP0877 09/112,760 IR16 PP0878  6,196,739 IR17 PP0879 09/112,774 IR18 PP0883  6,270,182 IR19 PP0880  6,152,619 IR20 PP0881 09/113,092 IR21 PO8006 6,087,638 MEMS02 PO8007  09/113,093 MEMS03 PO8008 09/113,062 MEMS04 PO8010  6,041,600 MEMS05 PO8011 09/113,082 MEMS06 PO7947  6,067,797 MEMS07 PO7944 09/113,080 MEMS09 PO7946  6,044,646 MEMS10 PO9393 09/113,065 MEMS11 PP0875 09/113,078 MEMS12 PP0894 09/113,075 MEMS13

FIELD OF THE INVENTION

[0003] The present invention relates to a method of enhancement image and, in particular, discloses a process for Utilising Exposure Information in a Digital Image Camera.

[0004] The present invention further relates to the field of digital image processing and in particular, the field of processing of images taken with a digital camera.

BACKGROUND OF THE INVENTION

[0005] Recently, digital cameras have become increasingly popular. These cameras normally operate by means of imaging a desired image utilising a charge coupled device (CCD) array and storing the imaged scene on an electronic storage medium for later down loading onto a computer system for subsequent manipulation and printing out. Normally, when utilising a computer system to print out an image, sophisticated software may be available to manipulate the image in accordance with requirements.

[0006] Unfortunately such systems require significant post processing of a captured image and normally present the image in an orientation in which it was taken, relying on a post processing process to perform any necessary or required modifications of the captured image. Further, much of the environmental information available when the picture was taken is lost.

SUMMARY OF THE INVENTION

[0007] It is an object of the present invention to provide for the utilisation of exposure information in an image specific manner.

[0008] In accordance with a first aspect of the invention there is provided a method of image enhancement of a sensed image taken with a digital camera, said digital camera being hand held and including an area image sensor, internal page width ink jet printer, processor means for processing an output of said area image sensor in accordance with processing rules, and a print roll including print media and printing ink for printing out a processed image on said print media, said digital camera further including an auto exposure setting means, said method comprising the step of utilising exposure setting information from said auto exposure setting means to process said sensed image in accordance with said processing rules.

[0009] In accordance with a second aspect of the invention there is provided a method of image enhancement of a sensed image taken with a digital camera, including an auto exposure setting means, said method comprising the step of utilising the auto exposure setting from said auto exposure setting means to process said sensed image to add exposure specific graphics to said image.

[0010] The utilising step can comprise utilising the auto exposure setting to determine a re-mapping of colours within the image so as to produce an amended image having colours within an image transformed to take account of the auto exposure setting. The processing can comprise re-mapping image colours so they appear deeper and richer when the exposure setting indicates low light conditions and re-mapping image colours to be brighter and more saturated when the auto exposure setting indicates bright light conditions.

[0011] The utilising step includes adding exposure specific graphics to the image.

BRIEF DESCRIPTION OF DRAWINGS

[0012] Notwithstanding any other forms which may fall within the scope of the present invention, preferred forms of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:

[0013]FIG. 1 illustrates the method of operation of the preferred embodiment.

DESCRIPTION OF PREFERRED AND OTHER EMBODIMENTS

[0014] The preferred embodiment is preferably implemented through suitable programming of a hand held camera device such as that described in the concurrently filed application U.S. Ser. No 09/113,060, entitled “A Digital Instant Printing Camera with Image Processing Capability” filed concurrently herewith by the present applicant the content of which is hereby specifically incorporated by cross reference and the details of which, and other related applications are set out in the tables included herein.

[0015] The aforementioned patent specification discloses a camera system, hereinafter known as an “Artcam” type camera, wherein sensed images can be directly printed out by an Artcam portable camera unit. Further, the aforementioned specification discloses means and methods for performing various manipulations on images captured by the camera sensing device leading to the production of various effects in any output image. The manipulations are disclosed to be highly flexible in nature and can be implemented through the insertion into the Artcam of cards having encoded thereon various instructions for the manipulation of images, the cards hereinafter being known as Artcards. The Artcam further has significant onboard processing power provided by an Artcam Central Processor unit (ACP) which is interconnected to a memory device for the storage of important data and image.

[0016] The invention disclosed in U.S. Ser. No. 09/113,060, relates to providing an alternative form of camera system which includes a digital camera with an integral color printer. Additionally, the camera provides hardware and software for the increasing of the apparent resolution of the image sensing system and the conversion of the image to a wide range of “artistic styles” and a graphic enhancement.

[0017] In accordance with the invention, disclosed in U.S. Ser. No. 09/113,060, there is provided a camera system comprising at least one area image sensor for imaging a scene, a camera processor means for processing said imaged scene in accordance with a predetermined scene transformation requirement, a printer for printing out said processed image scene on print media, print media and printing ink stored in a single detachable module inside said camera system, said camera system comprising a portable hand held unit for the imaging of scenes by said area image sensor and printing said scenes directly out of said camera system via said printer.

[0018] Preferably the camera system includes a print roll for the storage of print media and printing ink for utilization by the printer, the print roll being detachable from the camera system. Further, the print roll can include an authentication chip containing authentication information and the camera processing means is adapted to interrogate the authentication chip so as to determine the authenticity of said print roll when inserted within said camera system.

[0019] Further, the printer can include a drop on demand ink printer and guillotine means for the separation of printed photographs.

[0020] In the preferred embodiment, the Artcam has an auto exposure sensor for determining the light level associated with the captured image. This auto exposure sensor is utilised to process the image in accordance with the set light value so as to enhance portions of the image.

[0021] Preferably, the area image sensor includes a means for determining the light conditions when capturing an image. The area image sensor adjusts the dynamic range of values captured by the CCD in accordance with the detected level sensor. The captured image is transferred to the Artcam central processor and stored in the memory store. Intensity information, as determined by the area image sensor, is also forwarded to the ACP. This information is utilised by the Artcam central processor to manipulate the stored image to enhance certain effects.

[0022] Turning now to FIG. 1, the auto exposure setting information 1 is utilised in conjunction with the stored image 2 to process the image by utilising the ACP. The processed image is returned to the memory store for later printing out 4 on the output printer.

[0023] A number of processing steps can be undertaken in accordance with the determined light conditions. Where the auto exposure setting 1 indicates that the image was taken in a low light condition, the image pixel colours are selectively re-mapped so as to make the image colours stronger, deeper and richer.

[0024] Where the auto exposure information indicates that highlight conditions were present when the image was taken, the image colours can be processed to make them brighter and more saturated. The re-colouring of the image can be undertaken by conversion of the image to a hue-saturation-value (HSV) format and an alteration of pixel values in accordance with requirements. The pixel values can then be output converted to the required output colour format of printing.

[0025] Of course, many different re-colouring techniques may be utilised. Preferably, the techniques are clearly illustrated on the pre-requisite artcard inserted into the reader. Alternatively, the image processing algorithms can be automatically applied and hard-wired into the camera for utilization in certain conditions.

[0026] Alternatively, the Artcard inserted could have a number of manipulations applied to the image which are specific to the auto-exposure setting. For example, clip arts containing candles etc could be inserted in a dark image and large suns inserted in bright images.

[0027] It would be appreciated by a person skilled in the art that numerous variations and/or modifications may be made to the present invention as shown in the specific embodiment without departing from the spirit or scope of the invention as broadly described. The present embodiment is, therefore, to be considered in all respects to be illustrative and not restrictive.

[0028] The present invention is best utilized in the Artcam device, the details of which are set out in the following paragraphs.

[0029] Ink Jet Technologies

[0030] The embodiments of the invention use an ink jet printer type device. Of course many different devices could be used. However presently popular ink jet printing technologies are unlikely to be suitable.

[0031] The most significant problem with thermal ink jet is power consumption. This is approximately 100 times that required for high speed, and stems from the energy-inefficient means of drop ejection. This involves the rapid boiling of water to produce a vapor bubble which expels the ink. Water has a very high heat capacity, and must be superheated in thermal ink jet applications. This leads to an efficiency of around 0.02%, from electricity input to drop momentum (and increased surface area) out.

[0032] The most significant problem with piezoelectric ink jet is size and cost. Piezoelectric crystals have a very small deflection at reasonable drive voltages, and therefore require a large area for each nozzle. Also, each piezoelectric actuator must be connected to its drive circuit on a separate substrate. This is not a significant problem at the current limit of around 300 nozzles per print head, but is a major impediment to the fabrication of pagewidth print heads with 19,200 nozzles.

[0033] Ideally, the ink jet technologies used meet the stringent requirements of in-camera digital color printing and other high quality, high speed, low cost printing applications. To meet the requirements of digital photography, new ink jet technologies have been created. The target features include:

[0034] low power (less than 10 Watts)

[0035] high resolution capability (1,600 dpi or more)

[0036] photographic quality output

[0037] low manufacturing cost

[0038] small size (pagewidth times minimum cross section)

[0039] high speed (<2 seconds per page).

[0040] All of these features can be met or exceeded by the ink jet systems described below with differing levels of difficulty. Forty-five different ink jet technologies have been developed by the Assignee to give a wide range of choices for high volume manufacture. These technologies form part of separate applications assigned to the present Assignee as set out in the table under the heading Cross References to Related Applications.

[0041] The ink jet designs shown here are suitable for a wide range of digital printing systems, from battery powered one-time use digital cameras, through to desktop and network printers, and through to commercial printing systems

[0042] For ease of manufacture using standard process equipment, the print head is designed to be a monolithic 0.5 micron CMOS chip with MEMS post processing. For color photographic applications, the print head is 100 mm long, with a width which depends upon the ink jet type. The smallest print head designed is IJ38, which is 0.35 mm wide, giving a chip area of 35 square mm. The print heads each contain 19,200 nozzles plus data and control circuitry.

[0043] Ink is supplied to the back of the print head by injection molded plastic ink channels. The molding requires 50 micron features, which can be created using a lithographically micromachined insert in a standard injection molding tool. Ink flows through holes etched through the wafer to the nozzle chambers fabricated on the front surface of the wafer. The print head is connected to the camera circuitry by tape automated bonding.

[0044] Tables of Drop-on-Demand Ink Jets

[0045] Eleven important characteristics of the fundamental operation of individual ink jet nozzles have been identified. These characteristics are largely orthogonal, and so can be elucidated as an eleven dimensional matrix. Most of the eleven axes of this matrix include entries developed by the present assignee.

[0046] The following tables form the axes of an eleven dimensional table of ink jet types.

[0047] Actuator mechanism (18 types)

[0048] Basic operation mode (7 types)

[0049] Auxiliary mechanism (8 types)

[0050] Actuator amplification or modification method (17 types)

[0051] Actuator motion (19 types)

[0052] Nozzle refill method (4 types)

[0053] Method of restricting back-flow through inlet (10 types)

[0054] Nozzle clearing method (9 types)

[0055] Nozzle plate construction (9 types)

[0056] Drop ejection direction (5 types)

[0057] Ink type (7 types)

[0058] The complete eleven dimensional table represented by these axes contains 36.9 billion possible configurations of ink jet nozzle. While not all of the possible combinations result in a viable ink jet technology, many million configurations are viable. It is clearly impractical to elucidate all of the possible configurations. Instead, certain ink jet types have been investigated in detail. These are designated IJ01 to IJ45 which match the docket numbers in the table under the heading Cross References to Related Applications.

[0059] Other ink jet configurations can readily be derived from these forty-five examples by substituting alternative configurations along one or more of the 11 axes. Most of the IJ01 to IJ45 examples can be made into ink jet print heads with characteristics superior to any currently available ink jet technology.

[0060] Where there are prior art examples known to the inventor, one or more of these examples are listed in the examples column of the tables below. The IJ01 to IJ45 series are also listed in the examples column. In some cases, a print technology may be listed more than once in a table, where it shares characteristics with more than one entry.

[0061] Suitable applications for the ink jet technologies include: Home printers, Office network printers, Short run digital printers, Commercial print systems, Fabric printers, Pocket printers, Internet WWW printers, Video printers, Medical imaging, Wide format printers, Notebook PC printers, Fax machines, Industrial printing systems, Photocopiers, Photographic minilabs etc.

[0062] The information associated with the aforementioned 11 dimensional matrix are set out in the following tables. Dis- Description Advantages advantages Examples ACTUATOR MECHANISM (APPLIED ONLY TO SELECTED INK DROPS) Thermal An electrothermal Large force High power Canon bubble heater heats the generated Ink carrier Bubblejet ink to above Simple limited to 1979 Endo boiling point, construction water et al GB transferring No moving Low patent significant heat to parts efficiency 2,007,162 the aqueous ink. Fast High Xerox A bubble operation temperatures heater-in-pit nucleates and Small chip required 1990 quickly forms, area required High Hawkins et expelling the ink. for actuator mechamcal al USP The efficiency of stress 4,899,181 the process is Unusual Hewlett- low, with materials Packard TIJ typically less required 1982 Vaught than 0.05% of the Large drive et al USP electrical energy transistors 4,490,728 being transformed Cavitation into kinetic causes energy of the actuator drop. failure Kogation reduces bubble formation Large print heads are difficult to fabricate Piezo- A piezoelectric Low power Very large Kyser et al electric crystal such as consumption area required USP lead lanthanum Many ink for actuator 3,946,398 zirconate (PZT) is types can be Difficult to Zoltan USP electrically used integrate 3,683,212 activated, and Fast with 1973 either expands, operation electronics Stemme USP shears, or bends High High 3,747,120 to apply pressure efficiency voltage drive Epson to the ink, required transistors Stylus ejecting drops. Full page- Tektronix width print IJ04 heads impractical due to actuator size Requires electrical poling in high field strengths during manufacture Electro- An electric field Low power Low Seiko Epson, strictive is used to activate consumption maximum Usui et all JP electrostriction in Many ink strain 253401/96 relaxor materials types can (approx. IJ04 such as lead be used 0.01%) lanthanum Low Large area zirconate titanate thermal required for (PLZT) or lead expansion actuator due magnesium Electric to low strain niobate (PMN). field strength Response required speed is (approx. 3.5 marginal V/μm) can (˜10 μs) be generated High voltage without drive difficulty transistors Does not required require Full electrical pagewidth poling print heads impractical due to actuator size Ferro- An electric field Low power Difficult to IJ04 electric is used to induce consumption integrate a phase transition Many ink with between the types can electronics antiferroelectric be used Unusual (AFE) and Fast materials ferroelectric (FE) operation such as phase. Perovskite (<1 μs) PLZSnT are materials such as Relatively required tin modified lead high Actuators lanthanum longitudinal require a zirconate titanate strain large (PLZSnT) exhibit High area large strains of up efficiency to 1% associated Electric with the AFE to field strength FE phase of around transition. 3 V/μm can be readily provided Electro- Conductive plates Low power Difficult to IJ02, IJ04 static are separated by a consumption operate plates compressible or Many ink electrostatic fluid dielectric types can devices in (usually air). be used an aqueous Upon application Fast environment of a voltage, the operation The plates attract each electrostatic other and displace actuator will ink, causing drop normally ejection. The need to be conductive plates separated maybe in a comb from the ink or honeycomb Very large structure, or area required stacked to to achieve increase the high forces surface area High and therefore the voltage drive force. transistors may be required Full page- width print heads are not competitive due to actuator size Electro- A strong electric Low current High voltage 1989 Saito static field is applied to consumption required et al, USP pull on the ink, where- Low May be 4,799,068 ink upon electrostatic temperature damaged by 1989 Miura attraction sparks due et al, USP accelerates the to air 4,810,954 ink towards the breakdown Tone-jet print medium. Required field strength increases as the drop size decreases High voltage drive transistors required Electrostatic field attracts dust Permanent An electromagnet Low power Complex IJ07, IJ10 magnet directly attracts consumption fabrication electro- a permanent Many ink Permanent magnetic magnet, types can magnetic displacing ink and be used material causing drop Fast such as ejection. Rare operation Neodymium earth magnets High Iron Boron with a field efficiency (NdFeB) strength around 1 Easy required. Tesla can be extension High local used. Examples from single currents are: Samarium nozzles to required Cobalt (SaCo) pagewidth Copper and magnetic print heads metalization materials in the should be neodymium iron used for long boron family electro- (NdFeB, migration NdDyFeBNb, lifetime NdDyFeB, etc) and low resistivity Pigmented inks are usually infeasible Operating temperature limited to the Curie temperature (around 540 K) Soft A solenoid Low power Complex IJ01, IJ05, magnetic induced a consumption fabrication IJ08, IJ10, core magnetic field in Many ink Materials IJ12, IJ14, electro- a soft magnetic types can not usually IJ15, IJ17 magnetic core or yoke be used present in fabricated from a Fast a CMOS fab ferrous material operation such as such as electro- High NiFe, plated iron alloys efficiency CoNiFe, or such as CoNiFe Easy CoFe are [1], CoFe, or extension required NiFe alloys. from single High local Typically, the soft nozzles to currents magnetic material pagewidth required is in two parts, print heads Copper which are metalization normally held should be apart by a spring. used for long When the electro- solenoid is migration actuated, the two lifetime parts attract, and low displacing the resistivity ink. Electro- plating is required High saturation flux density is required (2.0-2.1 T is achievable with CoNiFe [1]) Lorenz The Lorenz force Low power Force acts IJ06, IJ11, force acting on a consumption as a twisting IJ13, IJ16 current carrying Many ink motion wire in a types can Typically, magnetic field is be used only a utilized. Fast quarter of This allows the operation the solenoid magnetic field to High length be supplied efficiency provides externally to the Easy force in a pnnt head, for extension useful example with rare from single direction earth permanent nozzles to High local magnets. pagewidth currents Only the current print heads required carrying wire Copper need be fabricated metalization on the print-head, should be simplifying used for materials long electro- requirements. migration lifetime and low resistivity Pigmented inks are usually infeasible Magneto- The actuator uses Many ink Force acts Fisehenbeck, striction the giant types can as a twisting USP magnetostrictive be used motion 4,032,929 effect of materials Fast Unusual IJ25 such as operation materials Terfenol-D (an Easy such as alloy of terbium, extension Terfenol-D dysprosium and from single are required iron developed at nozzles to High local the Naval pagewidth currents Ordnance print heads required Laboratory, hence High force Copper Ter-Fe-NOL). For is available metalization best efficiency, should be the actuator used for long should be pre- electro- stressed to migration approx. 8 MPa. lifetime and low resistivity Pre-stressing may be required Surface Ink under positive Low power Requires Silverbrook, tension pressure is held in consumption supple- EP 0771 reduction a nozzle by Simple mentary 658 A2 surface tension. construction force to and related The surface No unusual effect patent tension of materials drop applications the ink is reduced required in separation below the bubble fabrication Requires threshold, causing High special ink the ink to egress efficiency surfactants from the nozzle. Easy Speed may extension be limited by from single surfactant nozzles to properties pagewidth print heads Viscosity The ink viscosity Simple Requires Silverbrook, reduction is locally reduced construction supple- EP 0771 to select which No unusual mentary 658 A2 drops are to be materials force to and related ejected. A vis- required in effect drop patent cosity reduction fabrication separation applications can be achieved Easy Requires electrothermally extension special ink with most inks, from single viscosity but special inks nozzles to properties can be engineered pagewidth High speed for a 100:1 print heads is difficult viscosity to achieve reduction. Requires oscillating ink pressure A high temperature difference (typically 80 degrees) is required Acoustic An acoustic wave Can operate Complex 1993 is generated and without a drive Hadimioglu focussed upon the nozzle plate circuitry et al, EUP drop ejection Complex 550,192 region. fabrication 1993 Elrod Low et al, EUP efficiency 572,220 Poor control of drop position Poor control of drop volume Thermo- An actuator Low power Efficient IJ03, IJ09, elastic which relies upon consumption aqueous IJ17, IJ18, bend differential Many ink operation IJ19, IJ20, actuator thermal expansion types can requires a IJ21, IJ22, upon Joule be used thermal IJ23, IJ24, heating is used. Simple insulator on IJ27, IJ28, planar the hot side IJ29, IJ30, fabrication Corrosion IJ31, IJ32, Small chip prevention IJ33, IJ34, area required can be IJ35, IJ36, for each difficult IJ37, IJ38, actuator Pigmented IJ39, IJ40, Fast inks may be IJ41 operation infeasible, High as pigment efficiency particles may CMOS jam the bend compatible actuator voltages and currents Standard MEMS processes can be used Easy extension from single nozzles to pagewidth print heads High CTE A material with a High force Requires IJ09, IJ17, thermo- very high can be special IJ18, IJ20, elastic coefficient of generated material IJ21, IJ22, actuator thermal expansion Three (e.g. PTFE) IJ23, IJ24, (CTE) such as methods of Requires a IJ27, IJ28, polytetrafluoro- PTFE PTFE IJ29, IJ30, ethylene (PTFE) deposition deposition IJ31, IJ42, is used. As high are under process, IJ43, IJ44 GTE materials are develop- which is not usually non- ment: yet standard conductive, a chemical in ULSI fabs heater fabricated vapor PTFE from a conductive deposition deposition material is (CVD), spin cannot be incorporated. A coating, and followed 50 μm long PTFE evaporation with high bend actuator PTFE is a temperature with polysilicon candidate (above heater and 15 for low 350° C.) mW power input dielectric processing can provide 180 constant Pigmented μN force and 10 insulation inks may be μm deflection. in ULSI infeasible, Actuator motions Very low as pigment include: power particles may Bend consumption jam the bend Push Many ink actuator Buckle types can Rotate be used Simple planar fabrication Small chip area required for each actuator Fast operation High efficiency CMOS compatible voltages and currents Easy extension from single nozzles to pagewidth print heads Con- A polymer with a High force Requires IJ24 ductive high coefficient can be special polymer of thermal generated materials thermo- expansion (such Very low development elastic as PTFE) is power (High CTE actuator doped with consumption conductive conducting Many ink polymer) substances to types can Requires a increase its be used PTFE conductivity to Simple deposition about 3 orders of planar process, magnitude below fabrication which that of copper. Small chip is not yet The conducting area required standard in polymer expands for each ULSI fabs when resistively actuator PTFE heated. Fast deposition Examples of operation cannot be conducting High followed dopants include: efficiency with high Carbon nanotubes CMOS temperature Metal fibers compatible (above Conductive voltages and 350° C.) polymers such as currents processing doped Easy Evaporation polythiophene extension and CVD Carbon granules from single deposition nozzles to techniques pagewidth cannot print heads be used Pigmented inks may be infeasible, as pigment particles may jam the bend actuator Shape A shape memory High force Fatigue IJ26 memory alloy such as TiNi is available limits alloy (also known as (stresses of maximum Nitinol-Nickel hundreds of number of Titanium alloy MPa) cycles developed at the Large strain Low strain Naval Ordnance is available (1%) is Laboratory) is (more than required to thermally 3%) extend switched between High fatigue its weak corrosion resistance martensitic state resistance Cycle rate and its high Simple limited by stiffness austenic construction heat removal state. The shape Easy Requires of the actuator in extension unusual its martensitic from single materials state is deformed nozzles to (TiNi) relative to the pagewidth The latent austenic shape. print heads heat of The shape change Low voltage trans- causes ejection of operation formation a drop. must be provided High current operation Requires pre-stressing to distort the martensitic state Linear Linear magnetic Linear Requires IJ12 Magnetic actuators include Magnetic unusual Actuator the Linear In- actuators semi- duction Actuator can be conductor (LIA), Linear constructed materials Permanent with high such Magnet thrust, long as soft Synchronous travel, and magnetic Actuator high alloys (LPMSA), Linear efficiency (e.g. Reluctance using planar CoNiFe) Synchronous semi- Some Actuator (LRSA), conductor varieties Linear Switched fabrication also require Reluctance techniques permanent Actuator (LSRA), Long magnetic and the Linear actuator materials Stepper Actuator travel is such as (LSA). available Neodymium Medium iron boron force is (NdFeB) available Requires Low voltage complex operation multi-phase drive circuitry High current operation BASIC OPERATION MODE Actuator This is the Simple Drop Thermal directly simplest mode of operation repetition ink jet pushes operation: the No external rate is Piezoelectric ink actuator directly fields usually ink jet supplies sufficient required limited to IJ01, IJ02, kinetic energy to Satellite around IJ03, IJ04, expel the drop. drops can 10 kHz. IJ05, IJ06, The drop must be avoided However, IJ07, IJ09, have a sufficient if drop this is not IJ11, IJ12, velocity to velocity is the method, IJ14, IJ16, overcome the less than but IJ20, IJ22, surface tension. 4 m/s fundamental IJ23, IJ24, Can be to is related IJ25, IJ26, efficient, to the refill IJ27, IJ28, depending method IJ29, IJ30, upon the normally IJ31, IJ32, actuator used IJ33, IJ34, used All of the IJ35, IJ36, drop kinetic IJ37, IJ38, energy must IJ39, IJ40, be provided IJ41, IJ42, by the IJ43, IJ44 actuator Satellite drops usually form if drop velocity is greater than 4.5 m/s Proximity The drops to be Very simple Requires Silverbrook, printed are print head close EP 0771 selected by some fabrication proximity 658 A2 manner (e.g. can be used between the and related thermally induced The drop print head patent surface tension selection and the applications reduction of means does print media pressurized ink). not need to or transfer Selected drops are provide the roller separated from energy May require the ink in the required to two print nozzle by contact separate the heads with the print drop from printing medium or a the nozzle alternate transfer roller. rows of the image Monolithic color print heads are difficult Electra- The drops to be Very simple Requires Silverbrook, static printed are print head very high EP 0771 pull on selected by some fabrication electrostatic 658 A2 ink manner (e.g. can be used field and related thermally induced The drop Electrostatic patent surface tension selection field for applications reduction of means does small Tone-Jet pressurized ink). not need to nozzle sizes Selected drops are provide the is above air separated from energy breakdown the ink in the required to Electrostatic nozzle by a strong separate the field may electric field. drop from attract dust the nozzle Magnetic The drops to be Very simple Requires Silverbrook, pull on printed are print head magnetic ink EP 0771 ink selected by some fabrication Ink colors 658 A2 manner (e.g. can be used other than and related thermally induced The drop black are patent surface tension selection difficult applications reduction of means does Requires pressurized ink), not need to very high Selected drops are provide the magnetic separated from energy fields the ink in the required to nozzle by a strong separate the magnetic field drop from acting on the the nozzle magnetic ink. Shutter The actuator High speed Moving parts IJ13, IJ17, moves a shutter to (>50 kHz) are required IJ21 block ink flow to operation Requires ink the nozzle. The can be pressure ink pressure is achieved due modulator pulsed at a to reduced Friction and multiple of the refill time wear must be drop ejection Drop timing considered frequency. can be very Stiction is accurate possible The actuator energy can be very low Shuttered The actuator Actuators Moving parts IJ08, IJ15, grill moves a shutter to with small are required IJ18, IJ19 block ink flow travel can Requires ink through a grill to be used pressure the nozzle. The Actuators modulator shutter movement with small Friction and need only be force can wear must be equal to the width be used considered of the grill holes. High speed Stiction is (>50 kHz) possible operation can be achieved Pulsed A pulsed Extremely Requires an IJ10 magnetic magnetic field low energy external pull on attracts an ‘ink operation is pulsed ink pusher’ at the possible magnetic pusher drop ejection No heat field frequency. An dissipation Requires actuator controls problems special a catch, which materials prevents the ink for both the pusher from actuator moving when a and the drop is not ink pusher to be ejected. Complex construction AUXILIARY MECHANISM (APPLIED TO ALL NOZZLES) None The actuator Simplicity of Drop Most ink directly fires the construction ejection jets, ink drop, and Simplicity of energy including there is no operation must be piezoelectric external field or Small supplied by and thermal other mechanism physical size individual bubble. required. nozzle IJ01, IJ02, actuator IJ03, IJ04, IJ05, IJ07, IJ09, IJ11, IJ12, IJ14, IJ20, IJ22, IJ23, IJ24, IJ25, IJ26, IJ27, IJ28, IJ29, IJ30, IJ31, IJ32, IJ33, IJ34, IJ35, IJ36, IJ37, IJ38, IJ39, IJ40, IJ41, IJ42, IJ43, IJ44 Oscillating The ink pressure Oscillating Requires Silverbrook, ink oscillates, ink pressure external ink EP 0771 pressure providing much can provide pressure 658 A2 (including of the drop a refill oscillator and related acoustic ejection energy. pulse, Ink pressure patent stimu- The actuator allowing phase and applications lation) selects which higher amplitude IJ08, IJ13, drops are to be operating must be IJ15, IJ17, fired by speed carefully IJ18, IJ19, selectively The controlled IJ21 blocking or actuators Acoustic enabling nozzles. may operate reflections The ink pressure with much in the ink oscillation may be lower energy chamber achieved by Acoustic must be vibrating the print lenses can be designed for head, or used to focus preferably by the sound on an actuator in the nozzles the ink supply. Media The print head is Low power Precision Silverbrook, proximity placed in close High assembly EP 0771 proximity to the accuracy required 658 A2 print medium. Simple print Paper fibers and related Selected drops head may cause patent protrude from the construction problems applications print head further Cannot print than unselected on rough drops, and contact substrates the print medium. The drop soaks into the medium fast enough to cause drop separation. Transfer Drops are printed High Bulky Silverbrook, roller to a transfer roller accuracy Expensive EP 0771 instead of straight Wide range Complex 658 A2 to the print of print construction and related medium. A substrates patent transfer roller can can be used applications also be used for Ink can be Tektronix proximity drop dried on the hot melt separation. transfer piezoelectric roller ink jet Any of the IJ series Electro- An electric field Low power Field Silverbrook, static is used to Simple strength EP 0771 accelerate print head required for 658 A2 selected drops construction separation and related towards the print of small patent medium. drops is applications near or Tone-Jet above air breakdown Direct A magnetic field Low power Requires Silverbrook, magnetic is used to Simple magnetic ink EP 0771 field accelerate print head Requires 658 A2 selected drops of construction strong and related magnetic ink magnetic patent towards the print field applications medium. Cross The print head is Does not Requires IJ06, IJ16 magnetic placed in a require external field constant magnetic magnetic magnet field. The Lorenz materials Current force in a current to be densities canying wire is integrated may be high, used to move the in the resulting in actuator. print head electro- manu- migration facturing problems process Pulsed A pulsed Very low Complex IJ10 magnetic magnetic field is power print head field used to cyclically operation construction attract a paddle, is possible Magnetic which pushes on Small print materials the ink. A small head size required in actuator moves a print head catch, which selectively prevents the paddle from moving. ACTUATOR AMPLIFICATION OR MODIFICATION METHOD None No actuator Operational Many Thermal mechanical simplicity actuator Bubble amplification mechanisms Ink jet is used. The have IJ01, IJ02, actuator directly insufficient IJ06, IJ07, drives the drop travel, or IJ16, IJ25, ejection process. insufficient IJ26 force, to efficiently drive the drop ejection process Differ- An actuator Provides High stresses Piezoelectric ential material expands greater are involved IJ03, IJ09, expansion more on one side travel in a Care must be IJ17, IJ18, bend than on the other. reduced print taken that IJ19, IJ20, actuator The expansion head area the materials IJ21, IJ22, may be thermal, do not IJ23, IJ24, piezoelectric, delaminate IJ27, IJ29, magnetostrictive, Residual IJ30, IJ31, or other bend IJ32, IJ33, mechanism. The resulting IJ34, IJ35, bend actuator from high IJ36, IJ37, converts a high temperature IJ38, IJ39, force low travel or high IJ42, IJ43, actuator stress IJ44 mechanism to during high travel, formation lower force mechanism. Transient A trilayer bend Very good High stresses IJ40, IJ41 bend actuator where temperature are involved actuator the two outside stability Care must be layers are High speed, taken that identical. This as a new the materials cancels bend due drop can be do not to ambient fired before delaminate temperature and heat residual stress. dissipates The actuator only Cancels responds to residual transient heating stress of of one side formation or the other. Reverse The actuator Better Fabrication IJ05, IJ11 spring loads a spring. coupling to complexity When the actuator the ink High stress is turned off, the in the spring spring releases. This can reverse the force/distance curve of the actuator to make it compatible with the force/time requirements of the drop ejection. Actuator A series of thin Increased Increased Some stack actuators are travel fabrication piezoelectric stacked. This can Reduced complexity ink jets be appropriate drive Increased IJ04 where actuators voltage possibility require high of short electric field circuits strength, such as due to electrostatic and pinholes piezoelectric actuators. Multiple Multiple smaller Increases Actuator IJ12, IJ13, actuators actuators are used the force forces IJ18, IJ20, simultaneously to available may not add IJ22, IJ28, move the ink. from an linearly, IJ42, IJ43 Each actuator actuator reducing need provide only Multiple efficiency a portion of the actuators force required. can be positioned to control ink flow accurately Linear A linear spring is Matches Requires IJ15 Spring used to transform low travel print head a motion with actuator area for small travel and with higher the spring high force into a travel longer travel, requirements lower force Non-contact motion. method of motion trans- formation Coiled A bend actuator is Increases Generally IJ17, IJ21, actuator coiled to provide travel restricted IJ34, IJ35 greater travel in a Reduces to planar reduced chip area. chip area imple- Planar mentations imple- due to mentations extreme are relatively fabrication easy to difficulty fabricate. in other orientations. Flexure A bend actuator Simple Care must be IJ10, IJ19, bend has a small region means of taken not to IJ33 actuator near the fixture increasing exceed the point, which travel of elastic limit flexes much more a bend in the flexure readily than the actuator area remainder of the Stress actuator. The distribution actuator flexing is very is effectively uneven converted from an Difficult to even coiling to an accurately angular bend, model with resulting in finite greater travel of element the actuator tip. analysis Catch The actuator Very low Complex IJ10 controls a small actuator construction catch. The catch energy Requires either enables Very small external or disables actuator size force movement Unsuitable of an ink pusher for that is controlled pigmented in a bulk manner. inks Gears Gears can be used Low force, Moving parts IJ13 to increase travel low travel are required at the expense of actuators Several duration. Circular can be used actuator gears, rack and Can be cycles pinion, ratchets, fabricated are required and other gearing using More methods can be standard complex used. surface drive MEMS electronics processes Complex construction Friction, friction, and wear are possible Buckle A buckle plate Very fast Must stay S. Hirata plate can be used to movement within et al, “An change a slow achievable elastic limits Ink-jet Head actuator into a of the Using fast motion. It can materials for Diaphragm also convert a long device Micro- high force, low life actuator”, travel actuator High stresses Proc. IEEE into a high involved MEMS, Feb. travel, medium Generally 1996, force motion. high power pp 418-423. requirement IJ18, IJ27 Tapered A tapered Linearizes Complex IJ14 magnetic magnetic pole the magnetic construction pole can increase force/ travel at the distance expense of force. curve Lever A lever and Matches High IJ32, IJ36, fulcrum is used low travel stress IJ37 to transform a actuator with around the motion with small higher travel fulcrum travel and high requirements force into a Fulcrum motion with area has no longer travel and linear lower force. The movement, lever can also and can be reverse the used for a direction of fluid seal travel. Rotary The actuator is High Complex IJ28 impeller connected to a mechanical construction rotary impeller. A advantage Unsuitable small angular The ratio of for deflection of the force to pigmented actuator results in travel of the inks a rotation of the actuator impeller vanes, can be which push the matched to ink against the nozzle stationary vanes requirements and out of the by varying nozzle. the number of impeller vanes Acoustic A refractive or No moving Large area 1993 lens diffractive (e.g. parts required Hadimioglu zone plate) Only et al, EUP acoustic lens relevant 550,192 is used to for acoustic 1993 Elrod concentrate sound ink jets et al, EUP waves. 572,220 Sharp A sharp point is Simple Difficult to Tone-jet conductive used to con- construction fabricate point centrate an using electrostatic standard field. VLSI processes for a surface ejecting ink-jet Only relevant for electrostatic ink jets ACTUATOR MOTION Volume The volume of Simple High energy Hewlett- expansion the actuator construction is typically Packard changes, pushing in the case required to Thermal the ink in all of thermal achieve Ink jet directions. ink jet volume Canon expansion. Bubblejet This leads to thermal stress, cavitation, and kogation in thermal ink jet imple- mentations Linear, The actuator Efficient High IJ01, IJ02, normal moves in a coupling to fabrication IJ04, IJ07, to chip direction normal ink drops complexity IJ11, IJ14 surface to the print head ejected may be surface. The normal to required to nozzle is typically achieve the in the line of surface per- movement. pendicular motion Parallel The actuator Suitable for Fabrication IJ12, IJ13, to chip moves parallel to planar complexity IJ15, IJ33, surface the print head fabrication Friction IJ34, IJ35, surface. Drop Stiction IJ36 ejection may still be normal to the surface. Membrane An actuator with The effective Fabrication 1982 push a high force but area of the complexity Howkins small area is used actuator Actuator size USP to push a stiff becomes the Difficulty of 4,459,601 membrane that is membrane integration in contact with area in a VLSI the ink. process Rotary The actuator Rotary Device IJ05, IJ08, causes the levers may complexity IJ13, IJ28 rotation of some be used to May have element, such a increase friction grill or impeller travel at a pivot Small chip point area requirements Bend The actuator A very Requires the 1970 Kyser bends when small actuator to et al USP energized. This change in be made 3,946,398 may be due to dimensions from at 1973 differential can be least two Stemme thermal converted distinct USP expansion, to a large layers, or 3,747,120 piezoelectric motion. to have a IJ03, IJ09, expansion, thermal IJ10, IJ19, magnetostriction, difference IJ23, IJ24, or other form of across the IJ25, IJ29, relative actuator IJ30, IJ31, dimensional IJ33, IJ34, change. IJ35 Swivel The actuator Allows Inefficient IJ06 swivels around a operation coupling to central pivot. This where the the ink motion is suitable net linear motion where there are force on opposite forces the paddle applied to is zero opposite sides of Small chip the paddle, e.g. area Lorenz force. requirements Straighten The actuator is Can be used Requires IJ26, IJ32 normally bent, with shape careful and straightens memory balance of when energized. alloys where stresses to the austenic ensure that phase is the quiescent planar bend is accurate Double The actuator One Difficult IJ36, IJ37, bend bends in one actuator can to make IJ38 direction when be used to the drops one element is power two ejected by energized, and nozzles. both bend bends the other Reduced directions way when another chip size. identical. element is Not A small energized. sensitive efficiency to ambient loss temperature compared to equivalent single bend actuators. Shear Energizing the Can increase Not readily 1985 actuator causes a the effective applicable Fishbeck shear motion in travel of to other USP the actuator piezoelectric actuator 4,584,590 material. actuators mechanisms Radial The actuator Relatively High force 1970 con- squeezes an ink easy to required Zoltan striction reservoir, forcing fabricate Inefficient USP ink from a single Difficult to 3,683,212 constricted nozzles integrate nozzle. from glass with VLSI tubing as processes macroscopic structures Coil/ A coiled actuator Easy to Difficult to IJ17, IJ21, uncoil uncoils or coils fabricate fabricate for IJ34, IJ35 more tightly. The as a planar non-planar motion of the free VLSI devices end of the process Poor out-of- actuator ejects Small area plane the ink. required, stiffness therefore low cost Bow The actuator Can increase Maximum IJ16, IJ18, bows (or buckles) the speed travel is IJ27 in the middle of travel constrained when energized. Mechanic- High force ally rigid required Push-Pull Two actuators The Not readily IJ18 control a shutter. structure is suitable for One actuator pulls pinned at ink jets the shutter, and both ends, which the other pushes so has a directly it. high out-of- push plane rigidity the ink Curl A set of actuators Good fluid Design IJ20, IJ42 inwards curl inwards to flow to complexity reduce the the region volume of ink behind the that they enclose. actuator increases efficiency Curl A set of actuators Relatively Relatively IJ43 outwards curl outwards, simple large chip pressurizing ink construction area in a chamber surrounding the actuators, and expelling ink from a nozzle in the chamber. Iris Multiple vanes High High IJ22 enclose a volume efficiency fabrication of ink. These Small chip complexity simultaneously area Not suitable rotate, reducing for the volume pigmented between the inks vanes. Acoustic The actuator The Large area 1993 vibration vibrates at a high actuator required for Hadimioglu frequency. can be efficient et al, EUP physically operation at 550,192 distant from useful 1993 Elrod the ink frequencies et al, EUP Acoustic 572,220 coupling and crosstalk Complex drive circuitry Poor control of drop volume and position None In various ink jet No moving Various Silverbrook, designs the parts other EP 0771 actuator does tradeoffs are 658 A2 not move. required to and related eliminate patent moving parts applications Tone-jet NOZZLE REFILL METHOD Surface This is the normal Fabrication Low speed Thermal tension way that ink jets simplicity Surface ink jet are refilled. After Operational tension force Piezoelectric the actuator is simplicity relatively ink jet energized, it small IJ01-IJ07, typically returns compared to IJ10-IJ14, rapidly to its actuator IJ16, IJ20, normal position. force IJ22-IJ45 This rapid return Long refill sucks in air time usually through the dominates nozzle opening. the total The ink surface repetition tension at the rate nozzle then exerts a small force restoring the meniscus to a minimum area. This force refills the nozzle. Shuttered Ink to the nozzle High speed Requires IJ08, IJ13, oscillating chamber is Low actuator common ink IJ15, IJ17, ink provided at a energy, as pressure IJ18, IJ19, pressure pressure that the actuator oscillator IJ21 oscillates at twice need only May not be the drop ejection open or suitable for frequency. When close the pigmented a drop is to be shutter, inks ejected, the instead shutter is opened of ejecting for 3 half cycles: the ink drop ejection, drop actuator return, and refill. The shutter is then closed to prevent the nozzle chamber emptying during the next negative pressure cycle. Refill After the main High speed, Requires two IJ09 actuator actuator has as the independent ejected a drop a nozzle is actuators second (refill) actively per nozzle actuator is refilled energized. The refill actuator pushes ink into the nozzle chamber. The refill actuator returns slowly, to prevent its return from emptying the chamber again. Positive The ink is held a High refill Surface spill Silverbrook, ink slight positive rate, must be EP 0771 pressure pressure. After therefore a prevented 658 A2 the ink drop is high drop Highly and related ejected, the repetition hydrophobic patent nozzle chamber rate is print head applications fills quickly as possible surfaces are Alternative surface tension required for:, and ink pressure IJ01-IJ07, both operate to IJ10-IJ14, refill the nozzle. IJ16, IJ20, IJ22-IJ45 METHOD OF RESTRICTING BACK-FLOW THROUGH INLET Long inlet The ink inlet Design Restricts Thermal channel channel to the simplicity refill rate ink jet nozzle chamber is Operational May result Piezoelectric made long and simplicity in a ink jet relatively narrow, Reduces relatively IJ42, IJ43 relying on viscous crosstalk large chip drag to reduce area inlet back-flow. Only partially effective Positive The ink is under a Drop Requires a Silverbrook, ink positive pressure, selection and method EP 0771 pressure so that in the separation (such as a 658 A2 quiescent state can forces nozzle rim and related some of the ink be reduced or effective patent drop already Fast refill hydro- applications protrudes from time phobizing, Possible the nozzle. or both) to operation This reduces the prevent of the pressure in the flooding following: nozzle chamber of the IJ01-IJ07, which is required ejection IJ09-IJ12, to eject a certain surface of IJ14, IJ16, volume of ink. the print IJ20, IJ22, The reduction in head. IJ23-IJ34, chamber pressure IJ36-IJ41, results in a IJ44 reduction in ink pushed out through the inlet. Baffle One or more The refill Design HP Thermal baffles are placed rate is not complexity Ink Jet in the inlet ink as restricted May increase Tektronix flow. When the as the long fabrication piezoelectric actuator is inlet method. complexity ink jet energized, the Reduces (e.g. rapid ink crosstalk Tektronix movement creates hot melt eddies which Piezoelectric restrict the flow print heads). through the inlet. The slower refill process is unrestricted, and does not result in eddies. Flexible In this method Significantly Not Canon flap recently disclosed reduces applicable restricts by Canon, the backflow to most ink inlet expanding for edge- jet con- actuator (bubble) shooter figurations pushes on a thermal Increased flexible flap that ink jet fabrication restricts the inlet. devices complexity Inelastic deformation of polymer flap results in creep over extended use Inlet A filter is located Additional Restricts IJ04, IJ12, filter between the ink advantage refill rate IJ24, IJ27, inlet and the of ink May result IJ29, IJ30 nozzle chamber. filtration in complex The filter has a Ink filter construction multitude of small may be holes or slots, fabricated restricting ink with no flow. The filter additional also removes process particles which steps may block the nozzle. Small The ink inlet Design Restricts IJ02, IJ37, inlet channel to the simplicity refill rate IJ44 compared nozzle chamber May result to nozzle has a substantially in a smaller cross relatively section than that large chip of the nozzle, area resulting in easier Only ink egress out of partially the nozzle than effective out of the inlet. Inlet A secondary Increases Requires IJ09 shutter actuator controls speed of separate the position of a the inkjet refill shutter, closing print head actuator off the ink inlet operation and drive when the main circuit actuator is energized. The inlet The method Back-flow Requires IJ01, IJ03, is located avoids the problem is careful IJ05, IJ06, behind problem of inlet eliminated design to IJ07, IJ10, the ink- back-flow by minimize the IJ11, IJ14, pushing arranging the ink- negative IJ16, IJ22, surface pushing surface pressure IJ23, IJ25, of the actuator behind IJ28, IJ31, between the inlet the paddle IJ32, IJ33, and the nozzle. IJ34, IJ35, IJ36, IJ39, IJ40, IJ41 Part of The actuator and Significant Small IJ07, IJ20, the a wall of the ink reductions in increase in IJ26, IJ38 actuator chamber are back-flow fabrication moves to arranged so that can be complexity shut off the motion of the achieved the inlet actuator closes off Compact the inlet. designs possible Nozzle In some Ink back- None related Silverbrook, actuator configurations of flow to ink EP 0771 does not ink jet, there is problem is back-flow 658 A2 result in no expansion or eliminated on actuation and related ink back- movement of an patent flow actuator which applications may cause ink Valve-jet back-flow Tone-jet through the inlet. NOZZLE CLEARING METHOD Normal All of the nozzles No added May not be Most ink jet nozzle are fired complexity sufficient systems firing periodically, on the to displace IJ01, IJ02, before the ink has print head dried IJ03, IJ04, a chance to dry. ink IJ05, IJ06, When not in use IJ07, IJ09, the nozzles are IJ10, IJ11, sealed (capped) IJ12, IJ14, against air. IJ16, IJ20, The nozzle firing IJ22, IJ23, is usually IJ24, IJ25, performed during IJ26, IJ27, a special clearing IJ28, IJ29, cycle, after first IJ30, IJ31, moving the print IJ32, IJ33, head to a cleaning IJ34, IJ36, station. IJ37, IJ38, IJ39, IJ40, IJ41, IJ42, IJ43, IJ44, IJ45 Extra In systems which Can be Requires Silverbrook, power to heat the ink, but highly higher drive EP 0771 ink heater do not boil it effective voltage for 658 A2 under normal if the clearing and related situations, nozzle heater is May require patent clearing can be adjacent to larger drive applications achieved by over- the nozzle transistors powering the heater and boiling ink at the nozzle. Rapid The actuator is Does not Effectiveness May be used succession fired in rapid require depends with: IJ01, of actuator succession. extra drive substantially IJ02, IJ03, pulses In some circuits upon the IJ04, IJ05, configurations, on the configuration IJ06, IJ07, this may cause print head of the ink IJ09, IJ10, heat build-up at Can be jet nozzle IJ11, IJ14, the nozzle which readily IJ16, IJ20, boils the ink, controlled IJ22, IJ23, clearing the and initiated IJ24, IJ25, nozzle. In other by digital IJ27, IJ28, situations, it may logic IJ29, IJ30, cause sufficient IJ31, IJ32, vibrations to IJ33, IJ34, dislodge clogged IJ36, IJ37, nozzles. IJ38, IJ39, IJ40, IJ41, IJ42, IJ43, IJ44, IJ45 Extra Where an actuator A simple Not suitable May be used power to is not normally solution where there with: IJ03, ink driven to the limit where is a hard IJ09, IJ16, pushing of its motion, applicable limit to IJ20, IJ23, actuator nozzle clearing actuator IJ24, IJ25, may be assisted movement IJ27, IJ29, by providing an IJ30, IJ31, enhanced drive IJ32, IJ39, signal to the IJ40, IJ41, actuator. IJ42, IJ43, IJ44, IJ45 Acoustic An ultrasonic A high High IJ08, IJ13, resonance wave is applied to nozzle implement- IJ15, IJ17, the ink chamber. clearing ation IJ18, IJ19, This wave is of capability cost if IJ21 an appropriate can be system amplitude and achieved does not frequency to May be already cause sufficient implemented include force at the at very low an acoustic nozzle to clear cost in actuator blockages. This is systems easiest to achieve which if the ultrasonic already wave is at a include resonant acoustic frequency of the actuators ink cavity. Nozzle A microfabricated Can clear Accurate Silverbrook, clearing plate is pushed severely mechanical EP 0771 plate against the clogged alignment 658 A2 nozzles. The plate nozzles is required and related has a post for Moving patent every nozzle. A parts are applications post moves required through each There is nozzle, displacing risk of dried ink. damage to the nozzles Accurate fabrication is required Ink The pressure of May be Requires May be used pressure the ink is effective pressure with all pulse temporarily where pump IJ series increased so that other or other ink jets ink streams from methods pressure all of the nozzles. cannot actuator This may be used be used Expensive in conjunction Wasteful with actuator of ink energizing. Print A flexible ‘blade’ Effective Difficult Many ink jet head is wiped across for planar to use if systems wiper the print head print head print head surface. The surfaces surface is blade is usually Low cost non-planar fabricated from a or very flexible polymer, fragile e.g. rubber or Requires synthetic mechanical elastomer. parts Blade can wear out in high volume print systems Separate A separate heater Can be Fabrication Can be used ink is provided at the effective complexity with many IJ boiling nozzle although where other series ink heater the normal drop nozzle jets e-ection clearing mechanism does methods not require it. cannot The heaters do be used not require Can be individual implemented drive circuits, as at no many nozzles can additional be cleared cost in some simultaneously, ink jet con- and no imaging is figurations required. NOZZLEPLATE CONSTRUCTION Electro- A nozzle plate is Fabrication High Hewlett formed separately simplicity temperatures Packard nickel fabricated from and Thermal electroformed pressures Ink jet nickel, and are required bonded to the to bond print head chip. nozzle plate Minimum thickness constraints Differential thermal expansion Laser Individual nozzle No masks Each hole Canon ablated or holes are ablated required must be Bubblejet drilled by an intense UV Can be individually 1988 Sercel polymer laser in a nozzle quite fast formed et al., SPIE, plate, which is Some Special Vol. 998 typically a control over equipment Excimer polymer such as nozzle required Beam polyimide or profile is Slow where Applications, polysulphone possible there pp. 76-83 Equipment are many 1993 required is thousands of Watanabe relatively nozzles per et al., USP low cost print head 5,208,604 May produce thin burrs at exit holes Silicon A separate nozzle High Two part K. Bean, micro- plate is accuracy is construction IEEE machined micromachined attainable High cost Transactions from single Requires on Electron crystal silicon, precision Devices, and bonded to the alignment Vol. ED-25, print head wafer. Nozzles No. 10, may be 1978, pp clogged 1185-1195 by adhesive Xerox 1990 Hawkins et al., USP 4,899,181 Glass Fine glass No Very small 1970 Zoltan capillaries capillaries are expensive nozzle sizes USP drawn from glass equipment are difficult 3,683,212 tubing. This required to form method has been Simple to Not suited used for making make single for mass individual nozzles production nozzles, but is difficult to use for bulk manufacturing of print heads with thousands of nozzles. Mono- The nozzle plate High Requires Silverbrook, lithic, is deposited as a accuracy sacrificial EP 0771 surface layer using (<1 μm) layer 658 A2 micro- standard VLSI Monolithic under the and related machined deposition Low cost nozzle plate patent using techniques. Existing to form applications VLSI Nozzles are processes the nozzle IJ01, IJ02, litho- etched in the can be chamber IJ04, IJ11, graphic nozzle plate using used Surface IJ12, IJ17, processes VLSI lithography may be IJ18, IJ20, and etching. fragile IJ22, IJ24, to the IJ27, IJ28, touch IJ29, IJ30, IJ31, IJ32, IJ33, IJ34, IJ36, IJ37, IJ38, IJ39, IJ40, IJ41, IJ42, IJ43, IJ44 Mono- The nozzle plate High Requires IJ03, IJ05, lithic, is a buried etch accuracy long etch IJ06, IJ07, etched stop in the wafer. (<1 μm) times IJ08, IJ09, through Nozzle chambers Monolithic Requires IJ10, IJ13, substrate are etched in the Low cost a support IJ14, IJ15, front of the wafer, No wafer IJ16, IJ19, and the wafer is differential IJ21, IJ23, thinned from the expansion IJ25, IJ26 back side. Nozzles are then etched in the etch stop layer. No nozzle Various methods No nozzles Difficult to Ricoh 1995 plate have been tried to to become control drop Sekiya eliminate the clogged position et al USP nozzles entirely, accurately 5,412,413 to prevent nozzle Crosstalk 1993 clogging. These problems Hadimioglu include thermal et al EUP bubble 550,192 mechanisms and 1993 Elrod acoustic lens et al EUP mechanisms 572,220 Trough Each drop ejector Reduced Drop firing IJ35 has a trough manu- direction is through which a facturing sensitive to paddle moves. complexity wicking. There is no Monolithic nozzle plate. Nozzle slit The elimination No nozzles Difficult to 1989 Saito instead of of nozzle holes to become control drop et al USP individual and replacement clogged position 4,799,068 nozzles by a slit accurately encompassing Crosstalk many actuator problems positions reduces nozzle clogging, but increases crosstalk due to ink surface waves DROP EJECTION DIRECTION Edge Ink flow is along Simple Nozzles Canon (‘edge the surface of the construction limited to Bubblejet shooter’) chip, and ink No silicon edge 1979 drops are ejected etching High Endo et al from the chip required resolution is GB patent edge. Good heat difficult 2,007,162 sinking via Fast color Xerox substrate printing heater-in-pit Mech- requires one 1990 anically print head Hawkins strong per color et al USP Ease of chip 4,899,181 handing Tone-jet Surface Ink flow is along No bulk Maximum Hewlett- (‘roof the surface of the silicon ink flow is Packard TIJ shooter’) chip, and ink etching severely 1982 Vaught drops are ejected required restricted et al USP from the chip Silicon can 4,490,728 surface, normal to make an IJ02, IJ11, the plane of the effective IJ12, IJ20, chip. heat sink IJ22 Mechanical strength Through Ink flow is High ink Requires Silverbrook, chip, through the chip, flow bulk silicon EP 0771 forward and ink drops are Suitable etching 658 A2 (‘up ejected from the for and related shooter’) front surface of pagewidth patent the chip. print heads applications High nozzle IJ04, IJ17, packing IJ18, IJ24, density IJ27-IJ45 therefore low manu- facturing cost Through Ink flow is High ink Requires IJ01, IJ03, chip, through the chip, flow wafer IJ05, IJ06, reverse and ink drops are Suitable for thinning IJ07, IJ08, (‘down ejected from the pagewidth Requires IJ09, IJ10, shooter’) rear surface of print heads special IJ13, IJ14, the chip. High nozzle handling IJ15, IJ16, packing during IJ19, IJ21, density manufacture IJ23, IJ25, therefore IJ26 low manu- facturing cost Through Ink flow is Suitable for Pagewidth Epson actuator through the piezoelectric print heads Stylus actuator, which is print heads require Tektronix not fabricated as several hot melt part of the same thousand piezoelectric substrate as the connections ink jets drive transistors. to drive circuits Cannot be manu- factured in standard CMOS fabs Complex assembly required INK TYPE Aqueous, Water based ink Environ- Slow drying Most dye which typically mentally Corrosive existing contains: water, friendly Bleeds on ink jets dye, surfactant, No odor paper All IJ series humectant, and May ink jets biocide. strikethrough Silverbrook, Modem ink dyes Cockles EP 0771 have high water- paper 658 A2 fastness, light and related fastness patent applications Aqueous, Water based ink Environ- Slow drying IJ02, IJ04, pigment which typically mentally Corrosive IJ21, IJ26, contains: water, friendly Pigment IJ27, IJ30 pigment, No odor may clog Silverbrook, surfactant, Reduced nozzles EP 0771 humectant, and bleed Pigment 658 A2 biocide. Reduced may clog and related Pigments have an wicking actuator patent advantage in Reduced mechanisms applications reduced bleed, strike- Cockles Piezoelectric wicking and through paper ink-jets strikethrough. Thermal ink jets (with significant restrictions) Methyl MEK is a highly Very fast Odorous All IJ Ethyl volatile solvent drying Flammable series Ketone used for industrial Prints on ink jets (MEK) printing on various difficult surfaces substrates such as aluminum such as cans. metals and plastics Alcohol Alcohol based Fast drying Slight odor All IJ (ethanol, inks can be used Operates at Flammable series 2-butanol, where the printer sub-freezing ink jets and must operate at temperatures others) temperatures Reduced below the paper cockle freezing point Low cost of water. An example of this is in-camera consumer photographic printing. Phase The ink is solid No drying High Tektronix change at room time—ink viscosity hot melt (hot melt) temperature, instantly Printed ink piezoelectric and is melted in freezes on typically has ink jets the print head the print a ‘waxy’ feel 1989 Nowak before jetting. medium Printed USP Hot melt inks are Almost any pages may 4,820,346 usually wax print ‘block’ All IJ series based, with a medium can Ink ink jets melting point be used temperature around 80° C. No paper may be After jetting cockle above the the ink freezes occurs curie point almost instantly No wicking of permanent upon contacting occurs magnets the print medium No bleed Ink heaters or a transfer occurs consume roller. No power strikethrough Long warm occurs up time Oil Oil based inks are High High All IJ extensively used solubility viscosity: series in offset printing, medium for this is a ink jets They have some dyes significant advantages in Does not limitation improved cockle for use in characteristics on paper ink jets, paper (especially Does not which no wicking or wick through usually cockle). Oil paper require soluble dies and a low pigments are viscosity. required. Some short chain and multi- branched oils have a sufficiently low viscosity. Slow drying Micro- A microemulsion Stops ink Viscosity All IJ emulsion is a stable, self bleed higher than series forming emulsion High dye water ink jets of oil, water, and solubility Cost is surfactant. The Water, slightly characteristic oil, and higher than drop size is less amphiphilic water than 100 nm, and soluble based ink is determined by dies can High the preferred be used surfactant curvature of the Can stabilize con- surfactant. pigment centration suspensions required (around 5%) 

We claim:
 1. A method of image enhancement of a sensed image taken with a digital camera, said digital camera being hand held and including an area image sensor, internal page width ink jet printer, processor means for processing an output of said area image sensor in accordance with processing rules, and a print roll including print media and printing ink for printing out a processed image on said print media, said digital camera further including an auto exposure setting means, said method comprising the step of utilising exposure setting information from said auto exposure setting means to process said sensed image in accordance with said processing rules.
 2. A method as claimed in claim 1 wherein said utilising step comprises utilising the auto exposure setting from said auto exposure setting means to determine a re-mapping of colours within said image so as to produce an amended image having colours within an image transformed to take account of said auto exposure setting.
 3. A method as claimed in claim 2 wherein said processing comprises re-mapping image colours so they appear deeper and richer when said auto exposure setting indicates low light conditions.
 4. A method as claimed in claim 3 wherein said processing step comprises re-mapping image colours to be brighter and more saturated when said auto exposure setting indicates bright light conditions.
 5. A method as claimed in claim 1 wherein said utilising step includes adding exposure specific graphics to said image.
 6. A method of image enhancement of a sensed image taken with a digital camera, including an auto exposure setting means, said method comprising the step of utilising the auto exposure setting from said auto exposure setting means to process said sensed image to add exposure specific graphics to said image. 